The vallis shown in this figure is named for Timgad, a Roman colonial town in the Algerian Aurès Mountains, founded around 100 CE. The city was abandoned after an Arab invasion in the 8th century CE, before being covered by the Sahara. The city ruins were excavated in 1881. The city's population may have been as great as 15,000. This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit.

The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. During the first two years of orbital operations, MESSENGER acquired over 150,000 images and extensive other data sets. MESSENGER is capable of continuing orbital operations until early 2015.